Using risk analysis and Taguchi's method to find optimal conditions of design parameters: a case study

Variation in product performance can be seen as a design failure. The fundamental principle of robust design proposed by Taguchi is to improve the quality of a product by minimizing the effect of causes of variation, without totally eliminating the causes. A method of robust design is briefly explained and its application is demonstrated with the help of a case study from Roots Industries Ltd., Coimbatore. This paper describes how the inherent modeling of product and process requirements in key characteristics (KCs) can be used to express and capture the product design intent. KCs are those features which significantly affect product function and performance, or occur when there is variation. A prototype software program (VRM Tool) was developed to house all the critical design data for process optimization and its eventual reuse. We establish a systematic process of identifying, assessing and mitigating risk in the early stage of design for a Windtone class of automobile electric horn, using robust design concept. The results suggest that the proposed robust design method is an efficient, disciplined approach that can assist a product delivery team in designing for a better functional performance and improved reliability of the entire system .